Geissorhiza is a large genus of around 84 perennial species, of small to medium corm bearing plants in the Iridaceae family found in the winter rainfall region of the south and west coasts of southern Africa. Many of them make very handsome container plants and benefit from extra water during growth. The name Geissorhiza is derived from the Greek words geisson and rhiza which mean tile and root respectively. This is in reference to a tunic which covers the corms like a roof tile. The bulb-like structure is used as a storage organ during the dormant period. It is closely related to the genus Hesperantha, the main difference being that most Hesperantha are night bloomers.

Geissorhiza purpureolutea, synonymously known as Geissorhiza sulphurea var. sulphurea and commonly known as Milk Winecup, is a rare and near threatened South African endemic species found in the Western Cape province, extending from Piketberg south to Tulbagh and Paarl. It occurs in wet, sandy gravel fynbos flats that are poorly drained. Geissorhiza purpureolutea is a rare species with cream to yellow flowers with a dark brown to purple centre which are borne from late winter to early spring.